System and Method for Configuring Workstations

ABSTRACT

A method for managing an inventory system includes receiving an operation request that identifies an inventory item and selecting, from a plurality of workstations, a workstation at which to fulfill the operation request. The method also includes moving an inventory holder storing the identified inventory item to the selected workstation and moving a supply holder storing a supply item associated with the received operation request to the selected workstation. The method additionally includes fulfilling the operation request, at least in part, at the workstation.

TECHNICAL FIELD OF THE INVENTION

This invention relates, in general, to inventory systems and, moreparticularly, to a method and system for efficient delivery of supplyitems to a workstation.

BACKGROUND OF THE INVENTION

Modern inventory systems, such as those in mail-order warehouses,airport luggage systems, and custom-order manufacturing facilities, facesignificant challenges in responding to requests for inventory items. Itmay be particularly challenging to efficiently process operationrequests that involve supply items in addition to inventory items. Ininventory systems tasked with responding to large numbers of diverseoperation requests, slow responses to operation requests may result inan ever-increasing backlog of operation requests. Additionally, ininventory systems where certain tasks are performed at only certainstations, overall efficiency is hampered as the rigid distribution ofstations impedes throughput and adaptability.

SUMMARY OF THE INVENTION

In accordance with the present invention, the disadvantages and problemsassociated with inventory storage have been substantially reduced oreliminated. In particular, a mobile inventory system is provided thatincludes one or more mobile drive units capable of moving any of aplurality of inventory holders between locations within a physical spaceassociated with the mobile inventory system.

In accordance with one embodiment of the present invention, a method formanaging an inventory system includes receiving an operation requestthat identifies an inventory item and selecting, from a plurality ofworkstations, a workstation at which to fulfill the operation request.The method also includes moving an inventory holder storing theidentified inventory item to the selected workstation and moving asupply holder storing a supply item associated with the receivedoperation request to the selected workstation. The method additionallyincludes fulfilling the operation request, at least in part, at theworkstation.

In accordance with another embodiment of the present invention, a methodfor managing an inventory system includes receiving a plurality ofoperation requests and initiating fulfillment of one or more of theplurality of operation requests. The method also includes detecting atrigger event while fulfilling one or more of the plurality of operationrequests. Additionally, the method includes moving a supply holderstoring a supply item associated with the trigger event to a workstationassociated with the trigger event in response to detecting the triggerevent.

Technical advantages of certain embodiments of the present inventioninclude the ability to optimize the distribution and use of supplies inan inventory system. Additionally, certain embodiments may allowoperators to request delivery of supplies or other items involved inprocessing operation requests to a particular workstation, or tocustomize a workstation based on user input, orders received, or a setschedule. Additionally, certain embodiments may provide a flexible andscalable inventory management solution that can be easily adapted toaccommodate system growth and modification.

Other technical advantages of the present invention will be readilyapparent to one skilled in the art from the following figures,descriptions, and claims. Moreover, while specific advantages have beenenumerated above, various embodiments may include all, some, or none ofthe enumerated advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and itsadvantages, reference is now made to the following description, taken inconjunction with the accompanying drawings, in which:

FIG. 1 illustrates components of an inventory system according to aparticular embodiment;

FIG. 2 illustrates operation of a particular embodiment of the inventorysystem while retrieving an inventory holder containing particularinventory items and while retrieving a supply holder carrying supplyitems;

FIG. 3 illustrates particular embodiments of supply holders and supplyitems; and

FIG. 4 illustrates operation of a particular embodiment of the inventorysystem while retrieving and storing inventory holders and supplyholders.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates an inventory system 10 according to a particularembodiment of the present invention. Inventory system 10 includes amanagement module 15, one or more mobile drive units 20, one or moreinventory holders 30, one or more inventory items 40, one or moreworkstations 50, one or more supply holders 60, and one or more supplyitems 65. Mobile drive units 20 transport inventory holders 30 storinginventory items 40 and supply holders 60 storing supply items 65 betweenlocations within a workspace 70 in response to instructions communicatedby management module 15. As a result, inventory system 10 may be capableof efficiently completing tasks that involve both inventory items 40 andsupply items 65.

Management module 15 receives and/or generates operation requests 18that initiate particular operations involving inventory items 40 and/orsupply items 65 and transmits these operation requests 18 to appropriatecomponents of inventory system 10. Management module 15 may selectcomponents of inventory system 10 to perform the operations andcommunicate appropriate commands and/or data to the selected componentsto facilitate completion of these operations. Although the descriptionbelow focuses on embodiments of inventory system 10 that receiveoperation requests 18 from other components of inventory system 10,management module 15 may alternatively or additionally generateoperation requests 18 itself using any appropriate techniques. In suchembodiments, management module 15 may generate operation requests 18based on a predetermined schedule of operations, in response toreceiving a particular operation request 18, in response to detectingthe occurrence of a particular event, or based on any appropriateconsiderations.

Additionally, management module 15 may represent a single component,multiple components located at a central location within inventorysystem 10, and/or multiple components distributed throughout inventorysystem 10. For example, management module 15 may represent components ofone or more mobile drive units 20 that are capable of communicatinginfointation between the mobile drive units 20 and coordinating movementof mobile drive units 20 in transporting inventory holders 30 and supplyholders 60. More generally, however, management module 15 may includeany appropriate combination of hardware and/or software suitable toprovide the described functionality and may further include componentslocated on mobile drive units 20, workstations 50, or other elements ofinventory system 10.

Mobile drive units 20 move inventory holders 30 and supply holders 60between locations within workspace 70. Mobile drive units 20 mayrepresent any devices or components appropriate for use in inventorysystem 10 based on the characteristics and configuration of inventoryholders 30, supply holders 60 and/or other elements of inventory system10. In a particular embodiment of inventory system 10, mobile driveunits 20 represent independent, self-powered devices configured tofreely move about workspace 70. In alternative embodiments, mobile driveunits 20 represent elements of a tracked inventory system 10 configuredto move inventory holders 30 and supply holders 60 along tracks, rails,cables, or other guidance elements traversing workspace 70. In such anembodiment, mobile drive units 20 may receive power through a connectionto the guidance elements, such as a powered rail.

Additionally, mobile drive units 20 may be capable of communicating withmanagement module 15 to receive information identifying selectedinventory holders 30 and supply holder 60, transmit locations of mobiledrive units 20, or exchange any other suitable information to be used bymanagement module 15 or mobile drive units 20 during operation. Mobiledrive units 20 may communicate with management module 15 wirelessly,using wired connections between mobile drive units 20 and managementmodule 15, and/or in any other appropriate manner. As one example,particular embodiments of mobile drive unit 20 may communicate withmanagement module 15 and/or with one another using 802.11, Bluetooth, orany other appropriate wireless communication protocol. As anotherexample, in a tracked inventory system 10, tracks or other guidanceelement upon which mobile drive units 20 move may be wired to facilitatecommunication between mobile drive units 20 and other components ofinventory system 10.

Furthermore, as noted above, management module 15 may include componentsof individual mobile drive units 20. Thus, for the purposes of thisdescription, communication between management module 15 and a particularmobile drive unit 20 may represent communication between components of aparticular mobile drive unit 20. In general, mobile drive units 20 maybe powered, controlled, and propelled in any manner appropriate based onthe configuration and characteristics of inventory system 10.

Inventory holders 30 store inventory items 40. In a particularembodiment, inventory holders 30 include multiple storage bins with eachstorage bin capable of holding a different type of inventory item 40.Inventory holders 30 are capable of being carried, rolled, or otherwisemoved by mobile drive units 20. In particular embodiments, inventoryholder 30 may provide additional propulsion to supplement that providedby mobile drive unit 20 when moving inventory holder 30.

Inventory items 40 represent any objects suitable for storage in andretrieval by inventory system 10. For the purposes of this description,“inventory item 40” may represent any one or more objects of aparticular type that are stored in inventory system 10, while a “unit”of an inventory item 40 represents an individual object of that type.For example, in an inventory system 10 that stores books, a particularbook title may represent an “inventory item 40” while each individualcopy of that book may represent a “unit” of the inventory item 40. Thus,a particular inventory holder 30 is currently “storing” a particularinventory item 40 if the inventory holder 30 currently holds one or moreunits of that type. Similarly, two units of inventory may represent the“same” inventory item 40 if the units are of the same type.

As noted above, inventory items 40 may represent any objects suitablefor storage in inventory system 10. As one example, inventory system 10may represent a mail order warehouse facility, and inventory items 40may represent merchandise stored in the warehouse facility. Mobile driveunit 20 may retrieve a particular inventory holder 30 containing one ormore inventory items 40 requested in an order to be packed for deliveryto a customer.

As another example, inventory system 10 may represent an airport luggagefacility. In such an embodiment, inventory items 40 may represent piecesof luggage stored in the luggage facility. Mobile drive unit 20 mayretrieve inventory holder 30 containing luggage arriving and/ordeparting on particular flights or luggage destined for particular typesof processing, such as x-ray or manual searching.

As another example, inventory system 10 may represent amerchandise-return facility. In such an embodiment, inventory items 40may represent merchandise returned by customers. Units of theseinventory items 40 may be stored in inventory holders 30 when receivedat the facility. At appropriate times, a large number of units may beremoved from a particular inventory holder 30 and packed for shipmentback to a warehouse or other facility. For example, individual units ofa particular inventory item 40 may be received and stored in inventoryholders 30 until a threshold number of units of that inventory item 40have been received. A pallet may then be packed with inventory item 40and shipped to another facility, such as a mail-order warehouse.

As yet another example, inventory system 10 may represent amanufacturing facility, and inventory items 40 may represent individualcomponents intended for inclusion in an assembled product, such aselectronic components for a computer system. In such an embodiment,inventory system 10 may retrieve particular components so that a productassociated with an order can be built. Alternatively, in particularembodiments, inventory system 10 may represent a reconfigurable assemblyline in which each supply holders 60 hold equipment for a particularstage of assembly for one or more products manufactured by inventorysystem 10. The portable, reconfigurable nature of supply holders 60 may,in particular embodiments, allow inventory system 10 to dynamicallyassign tasks or stages of production to individual workstations 50 andallow inventory system 10 to adjust to variations in the output of thevarious stages of production. Although a number of example embodimentsare described, inventory system 10 may, in general, represent anysuitable facility or system for storing and processing inventory items40, and inventory items 40 may represent objects of any type suitablefor storage in a particular inventory system 10.

Workstations 50 represent locations designated for the removal ofinventory items 40 from inventory holders 30, the introduction ofinventory items 40 into inventory holders 30, the counting of inventoryitems 40 in inventory holders 30, and/or the processing or handling ofinventory items 40 in any other suitable manner. Workstations 50 alsorepresent locations where supply items 65 may be used to n facilitatethe processing or handling of inventory items 40. Workstations 50 mayalso include or incorporate any appropriate components for processing orhandling inventory items 40, such as scanners for monitoring the flow ofinventory items 40 in and out of inventory system 10, communicationinterfaces for communicating with management module 15, and/or any othersuitable components. Workstations 50 may be controlled, entirely or inpart, by human operators or may be fully automated.

Although “workstation” as used in the following description refers tolocations at which any appropriate processing operation supported byinventory system 10 may be completed, in particular embodiments ofinventory system 10 supply holder 60 may carry particular supply items65 to workstation 50 to facilitate the completion of tasks that may ormay not be completed by workstations 50 that do not have access to therelevant supply items 65. Thus, in particular embodiments, supply items65 may facilitate the creation of specialized workstations 50 that arecapable of performing a dynamically changing set of operations based onthe supply items 65 currently accessible to that workstation 50.

Supply holders 60 store supply items 65 that may facilitate completionof certain operations carried out by inventory system 10. By movingsupply holders 60 to appropriate workstations 50, inventory system 10may be capable of dynamically distributing supply items 65 withininventory system 10. In particular embodiments, supply holder 60 mayinclude multiple storage bins with each storage bin capable of holding adifferent type of supply items 65. As a result, a particular supplyholder 60 may, at a particular point in time, store multiple differenttypes of supply items 65.

Supply items 65 represent any suitable objects that facilitate thecompletion of a particular operation at workstations 50. As one example,in particular embodiments of system 10, supply items 65 may representexhaustible supplies used in the completion of tasks performed atworkstations 50. Thus, in particular embodiments in which inventorysystem 10 represents a mail order warehouse facility, supply items 65may represent or include invoices, gift-wrapping paper, tape, dunnage,envelopes, shipping containers, straps, desiccants, special sealants,labels, laminates, plaques, or any other appropriate object or objectssuitable to be included in an outgoing package or container.Additionally, these exhaustible supplies may represent reusable suppliesthat are used in the completion of tasks performed at workstations 50,such as totes, bins, hangers, clips, bindings, tape, wrapping, or anyother objects that are added to or removed from inventory item 40, andlater stored within inventory system 10 for reuse in subsequentoperations.

As another example, supply items 65 may represent machines, components,power supplies, batteries, parts, equipment, or tools appropriate foruse at workstation 50. In particular embodiments in which inventorysystem 10 represents a manufacturing facility, workstation 50 may bedynamically configured using one or more supply items 65. In suchembodiments, supply items 65, may represent or include engravers,etching machines, drills, saws, lathes, conveyors, or any otherappropriate devices suitable to facilitate operations on inventory items40 at workstation 50. Additionally, supply items 65 may represent itemsused in a kitting station, including tools, parts, components,materials, machines and associated working surfaces suitable to assembleinventory items 40. As a result, the use of a particular workstation 50may be changed by transporting particular, or particular combinationsof, supply items 65 to a particular workstation 50.

As yet another example, supply items 65 may represent items used toassist a human operator in performing operations at workstation 50. Insuch embodiments, supply items 65 may represent or include refreshments,trash cans, recycling bins, gloves, goggles, earplugs, towels, hygienicmaterials, and/or any other appropriate object or objects suitable tofacilitate a human operator in performing operations at workstation 50.For example, in particular embodiments, one or more supply holders 60may a supply item 65 representing a trash can or recycling bin, andinventory system 10 may be configured to circulate a supply holder 60 ofthis type to workstations 50 on a set schedule or at the request ofoperators. More generally, however, supply items 65 may include anyappropriate objects used by workstations 50 or operators of workstations50 in fulfilling operation requests generally, in fulfilling particulartypes of operation requests, or in fulfilling operation requests undercertain circumstances.

Workspace 70 represents an area associated with inventory system 10 inwhich mobile drive units 20 can move and inventory holders 30 and supplyholders 60 can be stored. For example, workspace 70 may represent all orpart of the floor of a mail-order warehouse in which inventory system 10operates. Although FIG. 1 shows, for the purposes of illustration, anembodiment of inventory system 10 in which workspace 70 includes afixed, predetermined, and finite physical space, particular embodimentsof inventory system 10 may include mobile drive units 20 that areconfigured to operate within a workspace 70 that is of variabledimensions and/or arbitrary geometry.

In operation, management module 15 receives operation requests 18 thattrigger particular operations within inventory system 10 including, butnot limited to, operations associated with the retrieval, assembly,storage, replenishment, and counting of inventory items 40. Operationrequests 18 may represent communication of any form suitable forinventory system 10 and may include any appropriate informationidentifying inventory items 40, supply items 65 and/or operations to becompleted by inventory system 10. Furthermore, although the descriptionbelow focuses on an embodiment of inventory system 10 capable ofperforming particular operations, a particular embodiment of inventorysystem 10 may be configured to perform any appropriate operationassociated with the storage, processing, or removal of inventory items40, and thus may receive operation requests 18 different from thosedescribed herein.

As noted above, management module 15 may receive operation requests 18from a human operator or other components of inventory system 10. Forexample, an operator of inventory system 10 may manually enter operationrequests 18 using a keyboard coupled to management module 15. As anotherexample, management module 15 may receive operation requests 18 fromremote components over a network connection, such as an internetconnection. Additionally, management module 15 may receive operationrequests 18 generated at workstation 50 or other elements of inventorysystem 10. Such operation requests 18 may be generated by a humanoperator or by a computer operating at workstation 50 or other elementof inventory system 10 in response to the occurrence of a particularevent or according to a predetermined schedule. Alternatively,management module 15 may itself generate operating requests. Forexample, management module 15 may be configured to initiate a particularoperation based on a predetermined schedule or in response to theoccurrence of a particular event, and may generate operation requests 18accordingly. In general, management module 15 may receive or generateoperation requests 18 in any suitable manner. For the sake ofillustration, however, the description below assumes that managementmodule 15 receives operation requests 18 from other elements ofinventory system 10.

In response to receiving an operation request 18, management module 15may select components or other elements of inventory system 10 tofulfill operation request 18. Depending on the type of operationrequested, management module 15 may select a particular mobile driveunit 20, inventory holder 30, supply holder 60, workstation 50, storagespace 90, and/or other suitable components and elements of inventorysystem to facilitate completion of the relevant operation request 18.Management module 15 may select the specific components for completing aparticular operation request 18 based on any appropriate considerations.As one example, management module 15 may, in particular embodiments,select a particular inventory holder 30 to complete an operation basedon factors including, but not limited to, its current distance from oneor more mobile drive units 20, the various types of inventory items 40stored by the selected inventory holder 30, its current location withinworkspace 70, other operation requests 18 the selected inventory holder30 is currently being used to fulfill, and/or the availability of anysupply items 65 that may be used in the operation. Similarly, managementmodule 15 may, in particular embodiments, select a particular supplyholder 60 to complete an operation based on a request for a particularinventory item 40, its current distance from one or more mobile driveunits 20, the various types of supply items 65 stored by the selectedsupply holder 60, its current location within workspace 70, otheroperation requests 18 the selected supply holder 60 is currently beingused to fulfill, and/or the availability of any supply items 65 that maybe used in the operation. As another example, management module 15 may,in particular embodiments, select a mobile drive unit 20 to fulfill aparticular task based on factors including, but not limited to, itsdistance from a selected inventory holder 30, a power supply levelassociated with the selected mobile drive unit 20, and/or its currentactivity. More generally, however, management module 15 may selectsuitable components to complete tasks associated with a particularoperation request 18 based on any appropriate factors, considerations,or criteria.

After management module 15 selects suitable components and/or elementsto complete operation request 18, management module 15 may thencommunicate information to the selected components indicating tasks tobe completed by these components or their operators and/or identifyingone or more of the other selected components involved in completion ofthe requested operation. For example, in the illustrated embodiment,management module 15 communicates one or more task requests 62 toselected components to communicate information regarding tasks to becompleted by the receiving components and/or other components to beinvolved in completing the relevant tasks. Task requests 62 mayrepresent communication of any suitable form to initiate completion oftasks by the receiving components, such as instructions, commands,and/or requests appropriately formatted for the receiving components.

The selected components may then utilize the received information tocomplete tasks associated with the relevant operation request 18. Forexample, based on instructions received from management module 15, aselected mobile drive unit 20 may move a selected inventory holder 30 toa selected workstation 50 so that an operator of the selectedworkstation 50 may pick requested inventory items 40 from the selectedinventory holder 30 and pack them for shipment. Similarly, a selectedmobile drive unit 20 may move a selected supply holder 60 carryingsupply items 65 to a selected workstation 50 to enable an operator atworkstation 50 to use supply items 65 to facilitate the processing orhandling of inventory items 40. FIG. 2 illustrates further the operationof a particular embodiment of inventory system 10 in responding toparticular types of operation requests 18.

When the selected supply holder 60 arrives at the selected workstation50, inventory system 10 may configure the selected supply holder 60 foruse or operation at the selected workstation 50. For example, inparticular embodiments, the selected mobile drive unit 20 may positionthe selected supply holder 60 so that a power cord of supply holder 60couples to an electrical outlet, battery, or other power supply locatedat the selected workstation 50. Similarly, mobile drive unit 20 mayconnect a hose of supply holder 60 to a supply for water, air, or anyother expendable resource (e.g., for use by tools on supply holder 60).More generally, however, mobile drive unit 20 or other components ofinventory system 10 may connect, open, activate, or otherwise configuresupply holder 60 for use at workstation 50.

As indicated above, supply holders 60 may be transported to workstations50 in response to any appropriate events and/or on any suitableschedule. Additionally, in particular embodiments, multiple supplyholders 60 may be transported to a particular workstation 50 within agiven time period so that a series of tasks may be carried out at therelevant workstation 50. Furthermore, the multiple supply holders 60 maybe transported to the relevant workstation 50 in a particular orderand/or arranged near the relevant workstation 50 in a particularconfiguration to facilitate an ordered series of tasks at the relevantworkstation 50, to permit certain supply holders 60 to align withcertain resources at the relevant workstation 50, and/or provide otherbenefits as these supply holders 60 are used to complete tasks at therelevant workstation 50.

As one example, in particular embodiments, a operation request 18 mayrequest the completion of an ordered sequence of multiple tasksassociated with a particular group of one or more inventory items 65,such as a series of steps in the manufacturing of a particularcomponent. Each task may be associated with a supply item 65 stored by adifferent supply holder 60, and management module 15 may instruct mobiledrive units 20 to position the supply holders 60 associated with thetask at or near the relevant workstation 50 based on the predeterminedorder of the tasks. For example, in an electronic manufacturing system,an operator of a workstation 50 may assemble a computer circuit board byattaching a series of inventory items 40 representing computer chips,capacitors, memory elements, and other electronic components to aprinted circuit board (PCB) using a particular order of tools andequipment. A first set of inventory items 40 may be soldered to thecircuit board using a soldering iron carried by a first supply holder60. A second set of inventory items 40 may be glued to the circuit boardusing a glue gun carried by a first supply holder 60. A third set ofinventory items may be screwed to the circuit board using an electricscrewdriver carried by a third supply holder 60 and a set of screwscarried by a fourth supply holder 60. As a result, inventory holders 30and supply holders 60 may queue at the relevant workstation 50 in aparticular order based on this sequence of tasks to be completed. Thus,management module 15 may instruct the appropriate mobile drive units 20to queue the supply holders based on the predetermined order in whichthe tasks will be completed so that mobile drive units 20 can move thefirst, second, third, and fourth supply holders 60 in order through aparticular location adjacent to the relevant workstation 50 whereoperator can reach and utilize the supplies carried by supply holders60. Alternatively, management module 15 may instruct mobile drive units20 to position supply holders 60 at locations around the relevantworkstation 50 based on the predetermined order in which the tasks willbe completed (e.g., with each of the four supply holders 60 positionedon a different side of the workstation 50). This may allow an operatorof the relevant workstation 50 to complete the tasks associated withassembling the computer card by turning from one position to the nextwith the circuit board in hand. More generally, management module 15 mayinstruct mobile drive units 20 to move supply holders 60 to the relevantworkstation 50 and/or position supply holders 60 relative to therelevant workstation 50 in an appropriate manner based on apredetermined order in which tasks associated with these supply holders60 will be completed.

As another example, supply holders 60 may be connect to, utilize, orotherwise interact with resources located at the relevant workstation50. For example, a supply holder 60 carrying a power tool as one of itssupply items 65 may connect to a supply for water, air, or any otherexpendable resource after being transported to the relevant workstation50. As a result, if multiple supply holders 60 are to be transported toa particular work station 50 at a given time, management module 15 mayinstruct mobile drive units 20 to position these supply holder 60 in aparticular manner to allow each supply holder 60 to connect to, utilize,or otherwise interact with the associated resources. Management module15 may also instruct mobile drive units 20 to move these supply holders60 to the relevant workstation in a particular order based on theresources associated with one or more of these supply holders 60 (e.g.,if movement near the relevant workstation 50 is constrained by nearbyequipment or other obstacles). More generally, management module 15 mayinstruct mobile drive units 20 to move supply holders 60 to the relevantworkstation 50 and/or position supply holders 60 relative to therelevant workstation 50 in an appropriate manner based on a resourceassociated with one or more of these supply holders 60.

FIG. 2 is an overhead view illustrating example operation of aparticular embodiment of inventory system 10 in responding to one ormore operation requests 18 in which one or more types of inventory items40 and supply items 65 are retrieved from and returned to storage spaces90 in workspace 70. In the illustrated embodiment, workspace 70 includesmultiple storage spaces 90, which represent physical locations whereinventory holders 30 and supply holders 60 rest when not being used torespond to operation requests 18. In the embodiment of inventory system10 illustrated by FIG. 2, inventory system 10 retrieves a selectedinventory holder 30 from a storage space 90 and moves the selectedinventory holder 30 to a selected workstation 50. Additionally, inresponse to a particular order received from a customer or theoccurrence of some other trigger event, such as a pre-determined timeperiod elapsing or a supply request being received from a workstation50, inventory system 10 may transport supply holders 60 to particularworkstations 50 or to all workstations 50 to facilitate completion ofoperation requests 18 at the relevant workstations 50.

After the appropriate inventory items 40 have been picked from inventoryholder 30, management module 15 may determine an appropriate storagespace 90 for the selected inventory holder 30 and instruct anappropriate mobile drive unit 20 to move the relevant inventory holder30 to the chosen storage space 90. Additionally, after a supply item 65or supply item carried by supply holder 60 has been used in fulfillingthe received operation request 18, inventory system 10 may determine anappropriate storage space 90 for the selected supply holder 60 and movethe selected supply holder 60 to the chosen storage space 90. Althoughthe description below describes inventory system 10 as performing aretrieval step and a storage step when responding to operation requests18, inventory system 10 may, in a particular embodiment, be configuredto perform operations when responding to retrieval requests.

In the illustrated example, management module 15 receives an operationrequest 18 that identifies one or more types of inventory items 40 to beretrieved from storage in inventory system 10. Operation request 18 mayadditionally identify one or more supply items 65 required to fulfill,complete, or otherwise facilitate processing of operation request.Depending on the configuration of inventory system 10, operation requestmay identify types of inventory items 40 to be retrieved, for example byspecifying a product name, or specific inventory items 40, for exampleby identifying particular articles of luggage.

In response to receiving operation request 18, management module 15 mayselect components or other elements of inventory system 10 to fulfilloperation request 18. Depending on the type of operation requested,management module 15 may select a particular mobile drive unit 20,inventory holder 30, workstation 50, supply holder 60 and/or othersuitable components and elements of inventory system to facilitatecompletion of the relevant operation request 18. As noted above,management module 15 may select the specific components for completing aparticular operation request 18 based on any appropriate considerations.After management module 15 selects suitable components and/or elementsto complete operation request 18, management module 15 may thencommunicate information to the selected components indicating tasks tobe completed by these components or their operators and/or identifyingone or more of the other selected components involved in completion ofthe requested operation. For example, in the illustrated embodiment,management module 15 communicates task requests 62 to selectedcomponents to communicate information regarding tasks to be completed bythe receiving components and/or other components to be involved incompleting the relevant tasks. Task requests 62 may representcommunication of any suitable form to initiate completion of tasks bythe receiving components, such as instructions, commands, and/orrequests appropriately formatted for the receiving components. Theselected components may then utilize the received information tocomplete tasks associated with the relevant operation request 18.

In the illustrated example, management module 15 responds to one or moreoperation requests 18 by selecting a workstation 50, one or moreinventory holders 30, one or more supply holders 60, and one or moremobile drive units 20 to fulfill operation request. As noted above,management module 15 may select these components based on anyappropriate considerations. FIG. 2 illustrates an example in whichmanagement module 15 selects four mobile drive units 20 (shown as mobiledrive units 20 a, 20 b, and 20 c), one inventory holder 30 (shown asinventory holder 30 a), and three supply holders 60 (shown as supplyholders 60 a, 60 b, and 60 c) to fulfill a received operation request 18at a selected workstation (shown as workstation 50 a, 50 b, 50 c, and 50d). After selecting the relevant components, management module 15 maycommunicate one or more task requests 62 to each of the selected mobiledrive units 20 to facilitate transport of the selected inventory holders30 and/or supply holders 60 to the selected workstation 50. The taskrequests 62 transmitted to each mobile drive unit 20 identify a selectedinventory holder 30 or supply holder 60 in terms of its location or anidentifier associated with the selected inventory holder 30 or supplyholder 60. The selected mobile drive units 20 may then move to theselected inventory holders 30 (as shown by arrows 210, 230, 250, and270) and dock with them. After docking, the selected mobile drive units20 begin moving the selected inventory holders 30 and supply holders 60towards the selected workstation 50 (as shown by arrows 220, 240, 260,280).

More specifically, in response to receiving operation request 18 a,identifying an inventory item 40 to be retrieved from inventory system10. To fulfill operation request 18 a, management module 15 selects aninventory holder 30 storing the identified inventory item 40 andcommunicates task request 62 a to selected mobile drive unit 20 a.Selected mobile drive unit 20 a moves to selected inventory holder 30 a,as shown by arrow 210 in FIG. 2, based on location or other informationspecified in task request 62 a. Selected mobile drive unit 20 a thencouples to selected inventory holder 30 a. After coupling to selectedinventory holder 30 a, selected mobile drive unit 20 a moves to selectedworkstation 50 h as shown by arrow 220 in FIG. 2.

In some embodiments of inventory system 10, some or all operationrequests 18 may identify a supply item 65 that is useful or necessary inprocessing or handling the requested inventory item 40. Thus, inparticular embodiments, supply items 65 are associated with particularselected operation requests 18. For example, in a mail-order warehouseembodiment of inventory system 10, an operation request may specify thata particular inventory item 40 to be packaged and shipped requiresgift-wrapping paper. In such embodiments, supply item 65 representsgift-wrapping paper associated with a particular operation request.Supply item 65 may additionally represent workspace, structural supportfor gift-wrapping paper, and any additional equipment on supply holder60 capable of facilitating the processing of inventory item 40. Asanother example, an operation request 18 may specify that an inventoryitem 40 to be packaged and shipped requires a pallet with particularstraps, or that an inventory item 40 to be packaged and shipped requiresparticular supply items 65 such as desiccants, special sealants, and/ormoisture control, or that a particular machine nr tool, such as anengraver or etching machine is required to process a particularinventory item 40. As a further example, in a manufacturing centerembodiment of inventory system 10, an operation request 18 may requestcustomization and/or modification of a particular inventory item 40, andmanagement module 15 may determine that a particular type of supply item65 is needed to perfon 1 the requested customization or modification. Asyet another example, an operation request 18 may request manufacture ofa particular inventory item 40, and management module 15 may determinethat a particular type of supply item 65 is needed to manufacture therequested inventory item 40.

In the example of FIG. 2, in response to determining that a supply item65 is associated with a received operation request 18, management module15 selects a supply holder 60 a that carries the relevant supply item 65and communicates task request 62 b to selected mobile drive unit 20 b.Selected mobile drive unit 20 b moves to selected supply holder 60 a, asshown by arrow 230 in FIG. 2, based on location or other informationspecified in task request 62 b. Selected mobile drive unit 20 b thencouples to selected supply holder 60 a and moves to selected workstation50 h as shown by arrow 240. Once in place at workstation 50 h, anoperator may use supply items 65 carried by supply holder 60 tofacilitate the processing, handling, and/or completion of the operation.

In other embodiments of inventory system 10, an operation request may begenerated by a particular workstation 50. In such embodiments,workstation 50 may communicate an operation request to management module15, or may select a particular mobile drive unit 20 to perform anoperation and may communicate an operation request directly to theselected mobile drive unit 20. Additionally, an operation request(referred to as a “supply request 64”) may be generated at a particularworkstation 50 in response to operator input, or in response to theoccurrence of a trigger event. For example, an operator at workstation50 b may provide input into inventory system 10 by requesting aparticular supply holder 60 or supply items 65. For instance, anoperator may request refreshments by pressing a “refreshments” button,or may request goggles, earplugs, or gloves an operator may desire for aparticular operation to be performed by pressing a relevant “goggles,”“earplugs,” or “gloves” button. In response to operator input,workstation 50 may communicate a supply request 64 directly to a mobiledrive unit 20, or may communicate supply request 64 to management module15. In the latter case, management module 15 then communicates a taskrequest 62 to a selected supply holder 60 that carries the requestedsupply item 65. As another example, workstation 50 may generate a supplyrequest 64 in response to an occurrence of a particular event. Forinstance, workstation 50 may include a supply holder 60 with a stock ofsupply items 65, such as power supplies included with a computer kit,dunnage to be included in packaging, tape to be used in sealing boxes,or hand wipes to assist in cleaning workstation 50. In such embodiments,workstation 50 may be configured to automatically generate a supplyrequest to replenish the stock of supply items 65 in response to theitem count, item weight, and/or any other appropriate threshold reachinga predetermined limit. Thus, inventory system 10 may automatically keepworkstation 50 supplied with supply items 65 without necessitatingoperator input.

In the illustrated example, workstation 50 b transmits a supply request64 to management module 15. In response to receiving supply request 64,management module 15 selects a supply holder 60 b that stores a supplyitem 65 requested by workstation 50 b, and communicates task request 62c to selected mobile drive unit 20 c. Selected mobile drive unit 20 cmoves to selected supply holder 60 b, as shown by arrow 250 in FIG. 2,based on location or other information specified in task request 62c.Selected mobile drive unit 20 c then couples to selected supply holder60 b, and moves to requesting workstation 50 b as shown by arrow 260.Once in place at workstation 50 b, an operator may use supply items 65carried by supply holder 60 to facilitate the processing, handling,and/or completion of operations at workstation 50 b or may resupply astock of the requested supply item 65 at workstation 50 b.

In other embodiments of system 10, supply requests 64 may be generatedby management module 15 or workstations 50 according to a predeterminedschedule. In such embodiments, certain supply holders 60 may betransported to workstations 50 at predetermined intervals. For instance,in mail-order warehouse embodiments of system 10, management module 15may be configured to transport a particular supply item 65 toworkstation each hour. In this example, supply item 65 may represent atrash bin or recycling bin transported to workstation 50. An operator atworkstation 50 may then expect to dispose of trash material once everyhour when supply holder 60 carrying supply item 65 is delivered. In amanufacturing center embodiment of inventory system 10, one or moresupply items 65 representing tools or parts used in facilitating theassembly of inventory items 40 may be transported to workstation 50 atpredetermined intervals. For instance, inventory system 10 may includedynamically configurable workstations 50 that may be changed by thehour, day, or other relevant time period according to the type of supplyitems 65 delivered to workstation 50. As an example, on day one, anoperator at workstation 50 may be assigned to use a drill press andlathe, and on the second day, assigned to use an engraver, and on thethird day, a drill press and lathe again. Thus, the particularconfiguration of workstation 50 may be configured to change dailyaccording to a repeatable schedule. Management module 15 may thentransport the selected supply holder 60 to workstation at regularintervals.

For example, in the illustrated embodiment, management module 15determines that a particular supply item 65 should be delivered to aparticular workstation 50 (here, workstation 50 a) based on apredetermined schedule. As a result, management module 15 selects asupply holder 60 c that carries the particular supply item 65 associatedwith the scheduled resupply, and communicates task request 62 d toselected mobile drive unit 20 d. Selected mobile drive unit 20 d movesto selected supply holder 60 c, as shown by arrow 270 in FIG. 2, basedon location or other information specified in task request 62 d.Selected mobile drive unit 20 d then couples to selected supply holder60 c, and moves to selected workstation 50 a as shown by arrow 280. Oncein place at workstation 50 a, an operator may use supply items 65carried by supply holder 60 c to facilitate the processing, handling,and/or completion of operations at workstation 50 a or to resupply astock of the relevant supply item 65 at workstation 50 a.

After being delivered to the appropriate workstations 50, the selectedsupply holders 60 may be returned to storage or otherwise relocatedwithin workspace 70. For example, in particular embodiments, managementmodule 15 may initiate storage of a particular supply holder 60 after anoperator of a workstation 50 indicates that the relevant supply holder60 is no longer needed at that workstation 50. Additionally,workstations 50 themselves may initiate storage of supply holder 60, forexample, by determining that supply items 65 carried by supply holder 60are exhausted. Additionally, management module 15 may decide to storesupply holder 60 after a mobile drive unit 20 and/or supply holder 60have remained at a particular workstation 50 for a predetermined lengthof time.

To store a supply holder 60, management module 15 may select a storagespace 90 based on any appropriate factors or considerations. Inparticular embodiments, management module 15 may group all supplyholders 60 in close proximity, or may group supply holders 60 carryingparticular supply items 65 in close proximity to associated inventoryitems 40. In general however, management module 15 may select anappropriate storage space 90 based on any relevant factors orconsiderations.

In the illustrated example, after selecting a storage space 90,management module 15 transmits task request 62 e to mobile drive unit 20e. Task request 62 e may include information identifying the selectedstorage space 90. Upon receiving task request 62 e, mobile drive unit 20e moves to workstation 50 e, as indicated in FIG. 2 by arrow 290. Mobiledrive unit 20 e then docks with supply holder 60 d, and moves supplyholder 60 d to the selected storage space 90, indicated in FIG. 2 byarrow 300. Mobile drive unit 20 e may then undock from supply holder 60d after arriving at the selected storage space 90. Mobile drive unit 20may then move away from the selected storage space 90, leaving supplyholder 60 in the selected storage space 90, and begin responding toother task requests 62.

Consequently, particular embodiments of inventory system 10 may providean optimized system of distributing supply items 65 to facilitate theprocessing or handling of inventory items 40. This may improve theability of operators at workstation 50 to increase the performance orthroughput of inventory system 10 by dynamically creating or alteringthe functions performed at a particular workstation 50. In particular,operators at workstation 50 may be able to provide input into inventorysystem 10 allowing them to request supply items 65, rather than leavingworkstation to search for supply items 65. Additionally, operators ofinventory system 10 may dynamically configure the operations performedat workstation 50 without having to alter the layout of workspace 70.Thus, an operator at workstation 50 may be performing etching one day,and drilling on the next day. As a result, particular embodiments ofinventory system 10 may provide significant operational benefits.Specific embodiments of inventory system 10, however, may provide some,none, or all of these benefits.

FIG. 3 illustrates example embodiments of supply holder 60 and supplyitems 65. Although particular examples are illustrated in FIG. 3,inventory system 10 may use other types of supply holder 60 and supplyitems 65. As shown in FIG. 3, supply holder 60 a represents a platformwith structural support for supply items 65 a. In the illustratedembodiment, supply items 65 a represent gift-wrapping paper, ribbons,cards, and tape. Collectively, supply holder 60 a and supply items 65 amay be referred to as a “gift-wrapping station.” A gift wrapping stationmay be utilized in particular embodiments in which inventory system 10represents a mail-order warehouse facility. In such embodiments,management module 15 may generate an operation request 18 in response tocustomer orders. As described above, management module 15 may select oneor more inventory holders 30 containing inventory items 40 to fulfill aparticular customer order. Additionally, if the customer order requiresgift wrapping, management module 15 may select supply holder 60 a,carrying supply items 45 a (the gift-wrapping paper, ribbons, cards, andtape). Management module 15 then generates a task request 62 to instructone or more mobile drive units 20 to transport inventory holder 30 andsupply holder 60 a to workstation 50. As a result, inventory items 40and supply items 65 a are available to an operator at workstation 50 toprocess. When an operator assembles a particular customer order, theoperator may utilize workspace on supply holder 60 a to gift wrap theinventory items 40. When completed, the operator may provide input intoinventory system 10, signaling that gift-wrapping is complete. Input maybe provided by manually entering a command on a keyboard coupled toworkstation 50, by pressing a “gift wrapping complete” button, or by anyother appropriate manner. In response, management module 15 may generatea task request 62, which instructs a mobile drive unit 20 to transportsupply holder 60 a to a storage space 90. Additionally, an operator atworkstation 50 may provide additional input to inventory system 10 whichsignals that gift-wrapping paper or other exhaustible supply items 65 aon supply holder 60 are running low. In response, management module 15may select a mobile drive unit 20, and generate a task request 62, thatinstructs the selected mobile drive unit 20 to transport supply holder60 a to an area for supply items 65 to be replenished. Although FIG. 3depicts a supply holder 60 a and supply items 65 as one example of asupply holder 60 carrying gift-wrapping paper to workstation 50,particular embodiments of inventory system 10 may include anyappropriate type of supplies, including, but not limited to, tape,dunnage, envelopes, shipping containers, straps, desiccants, specialsealants, labels, laminates, and/or plaques.

As shown in FIG. 3, supply holder 60 b represents a platform with aworkspace area and structural support for supply items 65 b. In thisexample, supply holder 60 b carries a supply item 65 b representing adrill press. Collectively, a supply holder 60 b carrying supply items 65b may be referred to as a “tool station.” In particular embodiments ofinventory system 10 in which inventory system 10 represents amanufacturing center, a tool station may be utilized to performoperations on particular inventory items 40. In such cases, an operatorat workstation 10 may provide input into inventory system 10, indicatingthat a tool station is required. Input may be provided by use of akeyboard coupled to workstation 50, by pressing a “drill press needed”button, or by any other appropriate manner. In response, managementmodule 15 may generate a task request 62, which instructs a mobile driveunit 20 to transport supply holder 60 b carrying supply item 65 b (inthis case, the drill press) to workstation 50. Once at workstation 50,an operator may utilize a workspace on supply holder 60 to performoperations using the supply item 65 on inventory item 40. In thisexample, an operator may use supply item 65 b to drill one or more holesin an inventory item 40. Once completed, the operator may again provideinput into inventory system 10 that signals that operation is complete.In response, management module 15 may generate a task request 62, whichinstructs a mobile drive unit 20 to transport supply holder 60 b to astorage space 90. Additionally, one or more supply holder 60 b may beutilized to dynamically configure the operation of workstation 50. Forexample, management module 15 may generate a task request 62 to one ormore mobile drive units 20 to transport one or more supply holders 60 toworkstation 50. At particular times during operation of inventory system10, a workstation 50 may be configured to use a supply holder 60 b toperform drill press operations, and another supply holder 60 b toperform sanding operations. An operator of workstation 50 or managementmodule 15 may dynamically configure the operations performed atworkstation 50 by requesting different or additional supply holders 60.For instance, an operator may provide input into inventory system 10,signaling that the operator no longer needs a drill press or a sander,and needs a lathe and an etching machine. Management module 15 may thenstore supply holders 60 carrying the drill press supply item 65 and thesanding supply item 65 in storage area 90, and transport to workstation50 a supply holder 60 carrying a lathe supply item 65 and a supplyholder carrying an etching machine supply item 65, in the mannerdescribed with respect to FIG. 2. In other embodiments, workstation 50may be dynamically configured according to a predetermined schedule.That is, particular supply holders 60 may arrive and depart workstation50 without regard to operator input. In this manner, workstation 50 maybe dynamically configured to support multiple types of operations, andmay be so configured based on any appropriate factors or considerations.Although FIG. 4 depicts a supply holder 60 b and supply items 65 b asone example of a supply holder 60 carrying a drill press supply item 65,particular embodiments of inventory system 10 may include anyappropriate type of tools, machines, components, and/or other equipment,including, but not limited to, engravers, etching machines, drills,saws, lathes, conveyors, or any other appropriate device suitable tofacilitate operations on inventory items 40 at workstation 50.

As shown in FIG. 3, supply holder 60 c represents a platform with aworkspace area and structural support for supply items 65 c. In thisexample, supply items 65 c represent containers for removal of itemsfrom workstation 50. In particular embodiments of inventory system 10,an operator at workstation 50 may remove items from inventory item 40 asinventory items 40 are processed. In such embodiments, an operator mayprovide input into inventory system 10, requesting a supply holder 60 cthat carries supply items 65 c. Additionally, management module 15 mayselect a supply holder 60 c carrying supply items 65 c based on theoperation performed at workstation 50, or any other appropriateconsiderations. Once in place at workstation 50, the operator may thendeposit items into supply items 65 c, and provide input into inventorysystem 10 when the supply items 65 c are full. Management module 15 maythen generate a task request 62, instructing a mobile drive unit 20 totransport supply holder 60 to another area of workspace 70 where thesupply items can be emptied or otherwise disposed of. In someembodiments of inventory system 10, items removed from inventory items40 may be reused by inventory system 10 in other areas of workspace 70.Additionally, management module 15 may generate a task request 62,instructing a mobile drive unit 20 to transport a supply holder 60 c toworkstation 50, as described above. Although FIG. 3 depicts a supplyholder 60 c and supply items 65 c as one example of a supply holder 60carrying supply items 65 c representing containers for removing items,particular embodiments of inventory system 10 may include anyappropriate types of containers or storage bins, including, but notlimited to, trash cans, recycling bins, shredding machines, and/or anyother appropriate device suitable to facilitate operations on inventoryitems 40 at workstation 50.

As shown in FIG. 3, supply holder 60 d represents a platform withstructural support for supply items 65 d. In this example, supply items65 d represent gloves, goggles, ear plugs, towels, sanitary wipes andother items designed to assist an operator in performing particularoperations at workstation 50. In particular embodiments of inventorysystem 10, an operator at workstation 50 may require articles ofclothing or other items designed to facilitate operations at workstation50. In such embodiments, an operator may provide input into inventorysystem 10, requesting gloves, goggles, ear plugs, towels or other supplyitems 65 carried on a supply holder 60 d. Additionally, managementmodule 15 may select a supply holder 60 c carrying supply items 65 cbased on the operation performed at workstation 50, or any otherappropriate considerations. For instance, if an operator requests asupply holder 60 carrying a table saw supply item 65, management module15 may automatically generate a task request 62 instructing a mobiledrive unit 20 to transport supply holder 60 d carrying a gloves supplyitem 65 d and a goggles supply item 65 d to workstation 50.Additionally, an operator may provide input to inventory system 10,requesting a particular supply item 65. An operator may provide input bya keyboard coupled to workstation 50, by pressing a button configured togenerate a predetermined operation request, or in any other appropriatemanner. For instance, an operator may request goggles, earplugs, orgloves by pressing a “goggles,” “earplugs,” or “gloves” button atworkstation 50. Although FIG. 3 depicts a supply holder 60 d and supplyitems 65 d as one example of a supply holder 60 carrying supply items 65c gloves, goggles, ear plugs, towels, sanitary wipes, particularembodiments of inventory system 10 may include any appropriate types ofitems suitable to facilitate operations on inventory items 40 atworkstation 50.

FIG. 4 is a flowchart illustrating example functionality of a particularembodiment of inventory system 10 in transporting a supply holder 60 toa workstation 50 in response to operator-generated input. Although FIG.4 illustrates a particular example of transporting a supply holder 60 toworkstation 50, other embodiments may transport supply holders 60 toworkstations 50 in response to received operation requests 18, inresponse to predetermined schedule, and/or in response to the occurrenceof any appropriate trigger event.

Additionally, although FIG. 4 illustrates steps executed in a particularembodiment of inventory system 10, alternative embodiments of inventorysystem 10 may perform all, some, or none of these steps and may do so inany appropriate order. Moreover, any two or more of the stepsillustrated in FIG. 4 may be combined, modified or deleted whereappropriate and additional steps may also be added.

In the described embodiment, the process begins at step 400 with anoperator requesting a particular supply item 65. For example, theoperator may be preparing to perform a hazardous operation atworkstation 50, and so requests goggles and gloves. The operator mayrequest goggles and gloves by providing input to inventory system 10. Anoperator may provide input by a keyboard coupled to workstation 50, ormay press a button configured to generate a predetermined operationrequest 18. For instance, the operator may press a “goggles” button torequest goggles, and may press a “gloves” button to request gloves.

Operation continues in step 402 with the workstation 50 communicating anoperation request 18 to management module 15. The particular operationrequest 18 is referred to herein as a “supply request 64.” Workstation50 may communicate supply request 64 to management module 15 through awired connection to management module, through a wireless network, viaradio frequencies, or by any other appropriate method. Additionally oralternatively, supply request 64 may be communicated to other elementsof inventory system 10, including one or more mobile drive units 20.

At step 404, management module 15 receives supply request 64 and selectsa supply holder 60 that carries the relevant supply items 65 to fulfillsupply request 64. As noted above, management module 15 may utilize anyappropriate criteria, factors, or considerations in selecting anappropriate supply holder 60. Examples of such factors may include, butare not limited to, the contents of supply holder 60, their locationrelative to workstations 50 or mobile drive units 20, existingassignments of supply holder 60, and/or any other appropriate factors.

At step 406, management module 15 selects a mobile drive unit 20 to movethe selected supply holder 60 to workstation 50. As noted above,management module 15 may also select the mobile drive unit 20 based anyappropriate factors, criteria, or considerations. Examples of suchfactors may include, but are not limited to, the location of mobiledrive units 20 relative to workstation 50 or the selected supply holder60. After selecting a supply holder 60 and a mobile drive unit 20,management module 15 transmits a task request 62, which containsinformation identifying workstation 50 and the selected supply holder60, to the selected mobile drive unit 20 at step 408.

After management module 15 has transmitted task request 62 to theselected mobile drive unit 20 in step 408, the selected mobile driveunit 20 moves the selected supply holder to the requesting workstation50 in step 410. In particular embodiments, the selected mobile driveunit 20 moves to the selected supply holder 60. The selected mobiledrive unit 20 then couples to the selected supply holder 60. Theselected mobile drive unit 20 then moves the selected supply holder 60to the workstation 50. The operator located at the selected workstation50 may then select or use the requested supply items 65 from theselected supply holder 60 in step 412.

In step 414, an operation request 18 may be generated at workstation 50indicating that supply holder 60 is ready to be transported to storagespace 90. The particular operation request 18 is referred to here as a“storage request.” This storage request may be generated at workstation50 in any appropriate manner. For example, the operator may provideinput to workstation 50 indicating that the operator has removed supplyitems 65 from supply holder 60, or has in some other way finished usingsupply items 65. In the example described above, the operator may removegloves and goggles from supply holder 60, and then signal that thegloves and goggles have been removed. For example, the operator mayprovide input by a keyboard coupled to workstation 50, or may press abutton configured to generate a predetermined operation request 18indicating that the operator no longer needs supply holder 60.Additionally, workstation 50 may generate a storage request after supplyholder 60 has remained at workstation 50 for a predetermined length oftime. As another example, in some embodiments of inventory system 10,supply holder 60 may be configured to detect when supply items 65 havebeen removed. In such embodiments, supply holder 60 itself may signal toworkstation 50, management module 15 or other relevant component ofworkstation 50 that supply holder 60 is ready to be transported tostorage space 90.

At step 416, management module 15 receives operation request 18 fromworkstation 50 and selects an available storage space 90 for the supplyholder 60 to be stored. At step 418, management module 15 transmits atask request 62 including information identifying the selected storagelocation 90 to the mobile drive unit 20 that transported the relevantsupply holder 60 or another selected mobile drive unit 20. Aftermanagement module 15 has transmitted this information to the appropriatemobile drive unit 20, the relevant mobile drive unit 20 moves supplyholder 60 to the selected storage location 90 at step 420. For example,in particular embodiments, the relevant mobile drive unit 20 moves thesupply holder 60 to the selected storage location 90 and then uncouplesfrom the supply holder 60. The relevant mobile drive unit 20 then movesaway, leaving the supply holder 60 behind in the selected storagelocation 90.

Furthermore, although the present invention has been described withseveral embodiments, a myriad of changes, variations, alterations,transformations, and modifications may be suggested to one skilled inthe art, and it is intended that the present invention encompass suchchanges, variations, alterations, transformations, and modifications asfall within the scope of the appended claims.

What is claimed is:
 1. A method for managing an inventory system, comprising: receiving an operation request that identifies an inventory item; selecting, from a plurality of workstations, a workstation at which to fulfill the operation request; moving an inventory holder storing the identified inventory item to the selected workstation; moving a supply holder storing a supply item associated with the received operation request to the selected workstation; and fulfilling the operation request, at least in part, at the workstation.
 2. The method of claim 1, wherein moving a supply holder storing a supply item associated with the received operation request to the selected workstation comprises: selecting a supply holder from a plurality of supply holders storing the supply item associated with the received operation request; and moving the selected supply holder to the selected workstation.
 3. The method of claim 2, wherein moving the selected supply holder to the selected workstation comprises: moving a mobile drive unit to the selected supply holder; and moving the selected supply holder to the selected workstation with the mobile drive unit.
 4. The method of claim 3, further comprising transmitting information identifying the selected workstation and the selected supply holder to the mobile drive unit.
 5. The method of claim 3, further comprising transmitting information identifying a location of the selected workstation and a location of the selected supply holder to the mobile drive unit.
 6. The method of claim 3, wherein moving the mobile drive unit to the selected supply holder comprises: moving the mobile drive unit to the selected supply holder; and docking the mobile drive unit with the selected supply holder.
 7. The method of claim 2, wherein selecting a supply holder comprises selecting a supply holder based, at least in part, on a distance between the selected supply holder and the selected workstation.
 8. The method of claim 2, wherein selecting a supply holder comprises selecting a supply holder based, at least in part, on a quantity of the supply item currently stored in the selected supply holder.
 9. The method of claim 2, wherein selecting a supply holder comprises selecting a supply holder based, at least in part, on a quantity of the supply item associated with the received operation request.
 10. The method claim 1, further comprising moving the supply holder to a storage location after moving the supply holder to the selected workstation.
 11. The method of claim 10, wherein moving the supply holder to the selected workstation comprises moving the supply holder from a first storage location to the selected workstation, and wherein moving the supply holder to a storage location comprises moving the supply holder to a second storage location.
 12. The method of claim 1, further comprising coupling the supply holder to a power supply at the workstation.
 13. The method of claim 1, wherein the supply holder comprises a first supply holder storing a first supply item for a first task associated with the received operation request, and further comprising moving a second supply holder storing a second supply item for a second task associated with the received operation request to the selected workstation.
 14. The method of claim 13, further comprising determining an order for moving the first supply holder and the second supply holder to the workstation based on a predetermined order associated with the first task and the second task.
 15. The method of claim 13, further comprising selecting, based on an order associated with the first task and the second task, positions for the first supply holder and the second supply holder; and wherein: moving the first supply holder to the selected workstation comprises moving the first supply holder to a first selected position; and moving the second supply holder the selected workstation comprises moving the second supply holder to a second selected position.
 16. The method of claim 13, further comprising selecting, based on a resource associated with at least one of the first supply holder and the second supply holder, positions for the first supply holder and the second supply holder; and wherein: moving the first supply holder to the selected workstation comprises moving the first supply holder to a first selected position; and moving the second supply holder the selected workstation comprises moving the second supply holder to a second selected position.
 17. An inventory system, comprising: one or more inventory holders operable to store inventory items; one or more supply holders operable to store supply items; a plurality of workstations at which operation requests are fulfilled; and a management module operable to: receive an operation request that identifies an inventory item; select, from the plurality of workstations, a workstation at which to fulfill the received operation request; initiate movement of an inventory holder storing the identified inventory item to the selected workstation; initiate movement of a supply holder storing a supply item associated with the received operation request to the selected workstation; and initiate fulfillment of the received operation request, at least in part, at the selected workstation.
 18. The system of claim 17, wherein the management module is operable to initiate movement of the supply holder by: selecting, from a plurality of supply holders, a supply holder storing the supply item associated with the received operation request; and initiating movement of the selected supply holder to the selected workstation.
 19. The system of claim 18, further comprising a mobile drive unit operable to move the selected supply holder, and wherein the management module is operable to initiate movement of the selected supply holder by: instructing the mobile drive unit to move to the selected supply holder; and instructing the mobile drive unit to move the selected supply holder to the selected workstation.
 20. The system of claim 19, wherein the mobile drive unit is further operable to couple the selected supply holder to a power supply at the selected workstation.
 21. The system of claim 19, wherein the management module is further operable to transmit information identifying the selected workstation and the selected supply holder to the mobile drive unit.
 22. The system of claim 19, wherein the management module is further operable to transmit information identifying a location of the selected workstation and a location of the selected supply holder to the mobile drive unit.
 23. The system of claim 19, wherein the mobile drive unit is further operable to dock with the selected supply holder.
 24. The system of claim 18, wherein the management module is operable to select a supply holder by selecting a supply holder based, at least in part, on a distance between the selected supply holder and the selected workstation.
 25. The system of claim 18, wherein the management module is operable to select a supply holder by selecting a supply holder based, at least in part, on a quantity of the supply item currently stored in the selected supply holder.
 26. The system of claim 18, wherein the management module is operable to select a supply holder by selecting a supply holder based, at least in part, on a quantity of the supply item associated with the received operation request.
 27. The system of claim 17, wherein the management module is further operable to initiate movement of the supply holder to a storage location after initiating movement of the supply holder to the selected workstation.
 28. The system of Claim. 27, wherein the management module is operable to initiate movement of the supply holder to the selected workstation by initiating movement of the supply holder from a first storage location to the selected workstation, and wherein the management module is operable to initiate movement of the supply holder to a storage location by initiating movement of the supply holder to a second storage location.
 29. The system of claim 17, wherein: the plurality of supply holders comprise a first supply holder storing a first supply item for a first task associated with the received operation request and a second supply holder storing a second supply item for a second task associated with the received operation request to the selected workstation; the management module is operable to initiate movement of a supply holder by initiating movement of the first supply holder to the selected workstation; and the management module is further operable to initiate movement of a second supply holder to the selected workstation.
 30. The system of claim 29, wherein the management module is further operable to determine an order for moving the first supply holder and the second supply holder to the workstation based on a predetermined order associated with the first task and the second task.
 31. The system of claim 29, wherein: the management module is further operable to select, based on an order associated with the first task and the second task, positions for the first supply holder and the second supply holder; the management module is operable to initiate movement of the first supply holder by initiating movement of the first supply holder to a first selected position; and the management module is operable to initiate movement of the second supply holder by initiating movement of the second supply holder to a second selected position.
 32. The system of claim 29, the management module is further operable to select, based on a resource associated with at least one of the first supply holder and the second supply holder, positions for the first supply holder and the second supply holder; the management module is operable to initiate movement of the first supply holder by initiating movement of the first supply holder to a first selected position; and the management module is operable to initiate movement of the second supply holder by initiating movement of the second supply holder to a second selected position.
 33. A computer software product, comprising instructions encoded in a tangible, computer-readable medium, the instructions operable when executed to: receive an operation request that identifies an inventory item; select, from a plurality of workstations, a workstation at which to fulfill the received operation request; initiate movement of an inventory holder storing the identified inventory item to the selected workstation; initiate movement of a supply holder storing a supply item associated with the received operation request to the selected workstation; and initiate fulfillment of the received operation request, at least in part, at the selected workstation.
 34. A method for managing an inventory system, comprising: receiving a plurality of operation requests; initiating fulfillment of one or more of the plurality of operation requests at one or more workstations; while fulfilling the one or more operation requests, detecting a trigger event; and in response to detecting the trigger event, moving a supply holder storing a supply item associated with the trigger event to a workstation associated with the trigger event.
 35. The method of claim 34, wherein: detecting the trigger event comprises determining that a predetermined amount of time has elapsed; and moving a supply holder storing a supply item associated with the trigger event to a workstation associated with the trigger event comprises moving a supply holder storing a supply item associated with the predetermined amount of time to a workstation associated with the predetermined amount of time.
 36. The method of claim 34, wherein: detecting the trigger event comprises receiving a supply request from a workstation associated with a particular supply item; and moving a supply holder to a workstation associated with the trigger event comprises moving a supply holder storing a supply item associated with the supply request to the workstation from which the supply request was received.
 37. The method of claim 34, further comprising coupling the supply holder to a power supply at the workstation.
 38. An inventory system, comprising: one or more supply holders storing supply items; a plurality of workstations at which operation requests are fulfilled; and a management module operable to: receive a plurality of operation requests; initiate fulfillment of one or more of the plurality of operation requests at one or more of the plurality of workstations; while the one or more operation requests are being fulfilled, detect a trigger event; and in response to detecting the trigger event, initiate movement of a supply holder storing a supply item associated with the trigger event to a workstation associated with the trigger event.
 39. The system of claim 38, wherein the management module is operable to: detect the trigger event by determining that a predetermined amount of time has elapsed; and initiate movement of a supply holder storing a supply item associated with the trigger event to a workstation associated with the trigger event by initiating movement of a supply holder storing a supply item associated with the predetermined amount of time to a workstation associated with the predetermined amount of time.
 40. The system of claim 38, wherein the management module is operable to: detect the trigger event by receiving a supply request from a workstation associated with a particular supply item; and initiate movement of a supply holder to a workstation associated with the trigger event by initiating movement of a supply holder storing a supply item associated with the supply request to the workstation from which the supply request was received.
 41. The system of claim 38, further comprising a plurality of mobile drive units operable to move the supply holders to the workstations.
 42. The system of claim 38, further comprising one or more mobile drive units, each of the mobile drive units operable to: move a supply holder to a workstation; and couple the moved supply holder to a power supply at the workstation.
 43. A computer software product, comprising instructions encoded in a tangible, computer-readable medium, the instructions operable when executed to: receive a plurality of operation requests; initiate fulfillment of one or more of the plurality of operation requests at one or more workstations; while the one or more operation requests are being fulfilled, detect a trigger event; and in response to detecting the trigger event, initiate movement of a supply holder storing a supply item associated with the trigger event to a workstation associated with the trigger event. 